Pneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. Many pneumothoraxes occur after physical trauma to the chest, blast injury, or as a complication of medical treatment. Pneumothoraxes may also occur spontaneously in people without chronic lung conditions or lung disease, and more rarely, in those without a prexisting lung condition.
The symptoms of a pneumothorax are determined by the size of the air leak (from the lungs into the pleural cavity) and the speed with which it occurs. Such symptoms may include chest pain (in most cases) and shortness of breath (in many). If a pneumothorax is left untreated, air may increasingly enter the pleural cavity and thus increasingly affect the ability of the lungs to expand and the person's ability to breathe. Eventually the lungs may be prevented from expanding. This situation is termed tension pneumothorax. A tension pneumothorax will lead to severe oxygen shortage and low blood pressure, and will progress to cardiac arrest and death. It must be treated if the person is to survive.
The common procedure to treat a tension pneumothorax is to insert a hypodermic needle into the chest between the 2nd and the 3rd ribs into the pleural cavity, and to evacuate the air through the hypodermic needle by means of a syringe. After evacuation of the air the lungs should be able to expand fully again, and normal respiration should thereby be re-established (although this procedure may need to be repeated).
Medical personnel and emergency response personnel may be called on diagnose and treat a tension pneumothorax in urgent or emergency situations. The training of such medical and emergency personnel in such diagnosis and treatment is usually carried out on patient simulating mannequins. Such mannequins can simulate the symptoms of a tension pneumothorax and allow for the insertion of needle therein to simulate the treatment of a tension pneumothorax. Specifically a tension pneumothorax may be simulated by limiting the visible chest rise of the mannequin and/or by giving auditory clues to the trainee.
For treatment of the mannequin, a container located in the chest of the mannequin at the correct location (to simulate air in the pleural cavity) is filled with pressured air. The air pressure in the container is monitored by a pressure sensor. If the trainee performs a correct needle decompression by inserting a hypodermic needle through the chest skin and into the container, the pressured air is released to the environment through the needle. The pressure drop is detected by the mannequin's electronics and the mannequin starts to “breath” normally again.
Improvements in patient simulating mannequin technology have occurred over time, including in the area of tension pneumothorax simulation. For example, US Published Patent Application No. 2009/0291421 A1 (published Nov. 26, 2009, entitled “Simulator For Medical Training With Detachable Self-Sealing Hollow Member”—hereinafter the '421 Publication) describes, according to the abstract thereof, a “[s]imulator for medical training having at least a detachable, fluid-tight hollow member comprising: at least a portion . . . made of a self-sealing material; an opening . . . to fill said hollow member with a fluid, said opening . . . being provided with closure means . . . or being connected . . . to closure means; fastening means . . . to detachably fasten said hollow member to said simulator. The portion made of self-sealing material allows multiple punctures before having to be replaced.” Notwithstanding the advancements described in the '421 Publication, improvements in this area are still possible.